Culture conversion and macrolide resistance in <i>Mycobacterium abscessus</i> complex pulmonary disease

The <i>Mycobacterium abscessus</i> complex (MABC) is highly resistant to antibiotics, making <i>Mycobacterial abscessus</i> pulmonary disease (MAPD) difficult to treat. Macrolide antibiotics are the main treatment, but there is debate over whether azithromycin (AZI) or clarithromycin (CLA) is more effective. In our study of 61 MAPD patients, we compared the effectiveness of AZI and CLA while tracking resistance. We found that the minimum inhibitory concentrations (MICs) of AZI were four to eight times higher than those of CLA. Isolates with the functional <i>erm</i>(41) gene exhibited macrolide resistance, with AZI developing resistance faster than CLA. Patients with these resistant strains had lower rates of successful treatment. Overall, the <i>in vitro</i> sensitivity and the inducible resistance occurrence all favor CLA over AZI for MABC-PD treatment.